More than 140,000 fish die at Mowi farm in Norway
Acute and chronic gill problems blamed for mortality
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More than 140,000 farmed salmon died at Mowi Norway’s “Krabbestig” site in the period from November 1 to 21, 2025, documents seen by Fish Farming Expert’s Norwegian sister site, Kyst.no, show.
The mortality is documented in an inspection report from the Norwegian Food Safety Authority (Mattilsynet), carried out after the company reported increased mortality related to gill problems.
The fish farm is in Kinn municipality, in Vestland county.
According to the report, approximately 10.35% of the fish at the site died. Some pens had significantly higher mortality rates, including one cage with more than 40% loss. According to the report, the mortality is linked to both acute and chronic gill problems.
Unacceptable situation
During the inspection on November 25, Mattilsynet observed fish with respiratory problems, and autopsied fish showed pinpoint bleeding on the gills. Mattilsynet considered the situation to be unacceptable from a fish welfare perspective and ordered Mowi to implement measures to ensure proper operations at the site.
At the same time, it was revealed that the location was above the permitted limit for sea lice. In week 48, an average of 4.31 adult female lice per fish was reported. Mattilsynet therefore also notified a decision on measures to get below the lice limit, with possible culling as a consequence if the requirements were not met.
Harvesting out
In a comment to Kyst.no, Mowi stated that the company had decided to harvest all fish at the site.
“Despite improvement in recent weeks, we have decided to harvest the locality Krabbestig out of consideration for fish welfare,” wrote communications director Morten Bertelsen.
He further stated that the company does not yet have a definitive explanation for the cause of the problems.
“We have indications that a water-borne agent may have had a negative impact in the area, but there is currently no final conclusion on the cause of the gill problems,” wrote Bertelsen.
Kyst.no has also asked Mowi how many fish died in total in November, but the fish farming company has not been willing to provide an answer.
